U.S. and Iraqi troops killed 30 militants early on Sunday (October 8) in fierce fighting in the flashpoint southern Shi'ite city of Diwaniya, the U.S. military said. The military said an M1A2 Abrams tank was severely damaged in the battle that erupted after militants opened fire with rocket-propelled grenades on U.S. and Iraqi forces on a mission to detain a "high-value" target. Diwaniya's southern districts are a stronghold for the Mehdi Army militia of Shi'ite cleric Moqtada al-Sadr, whose movement is a key player in the Prime Minister Nuri al-Maliki's government of national unity. A Mehdi Army official, who declined to be named, denied any involvement in the fighting and blamed rogue gunmen. He said Sadr had issued orders to the Mehdi Army "not to attack anybody, including the Americans". Another Mehdi Army official denied reports of the 30 killed and said only three people had been wounded. Hospital sources said four civilians were wounded, three men and a woman. Maliki, under increasing pressure from Washington, has vowed to crack down on militias, which are blamed for much of the violence fuelling the Sunni-Shi'ite sectarian conflict. "At 0730 a.m. the Americans came because a U.S. tank was burnt...I saw the tank. What has happened is that a bomb exploded at the Americans. I saw the tank on fire and a (U.S.) vehicle arrived to put out the fire," said one eyewitness. By midday, Diwaniya, 180 km (115 miles) south of Baghdad, was reported to be quiet, but there was a heavy U.S. military presence. U.S. and Iraqi troops have launched numerous operations in recent weeks against the Mehdi Army in their hunt for sectarian death squads accused of carrying out indiscriminate killings. The U.S. military statement said a high-value target, whom it did not name, had been captured by Iraqi troops during the operation. It said the suspect was accused of involvement in the deaths of Iraqi soldiers on Aug. 28, when 20 soldiers were killed in a battle with Shi'ite militiamen in the city.